/*
* Artificial Intelligence for Humans
* Volume 2: Nature Inspired Algorithms
* Java Version
* http://www.aifh.org
* http://www.jeffheaton.com
*
* Code repository:
* https://github.com/jeffheaton/aifh
*
* Copyright 2014 by Jeff Heaton
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*     http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* For more information on Heaton Research copyrights, licenses
* and trademarks visit:
* http://www.heatonresearch.com/copyright
*/
package com.heatonresearch.aifh.error

/**
* An abstract error calculation class that provides some basic functionality.
*/
abstract class AbstractErrorCalculation extends ErrorCalculation {

  /**
   * The overall error.
   */
  protected var globalError: Double = 0.0
  /**
   * The size of a set.
   */
  protected var setSize: Int = 0

  override def updateError(actual: Array[Double], ideal: Array[Double], significance: Double) {
    // TODO should this 0 out globalError as per below fn
    for(i <- 0 until actual.length) {
      val delta = (ideal(i) - actual(i)) * significance
      globalError += delta * delta
    }
    setSize += ideal.length
  }

  override def updateError(actual: Double, ideal: Double) {
    val delta = ideal - actual
    globalError += delta * delta
    setSize += 1
  }

  override def clear() {
    globalError = 0
    setSize = 0
  }

  override def getSetSize: Int = setSize
}